diff --git a/readme.md b/readme.md
index f0555c9..902a21d 100644
--- a/readme.md
+++ b/readme.md
@@ -127,7 +127,8 @@ Put differently: it starts executing instructions at the address contained in `$
     LDA *           ; `*` is a special label referencing the memory address
                     ; where the current line will be stored after assembly
 
-- Hexadecimal numbers are preceded by a `$`
+- Prefix hexadecimal numbers with `$` (or `0x`)
+- Prefix binary numbers with `0b`
 - Whitespace is ignored
 
 ## Cardiograph memory map